Well, if you were able to connect once before and you can't right now, it kind of points towards a module conflict. Can you open up the Terminal and post the results of:
The first command will tell us what modules are loaded. The second command will tell us what driver is being used. The third will tell us what modules are not supposed to load. The fourth will tell us what we want to have load.
lsmod|grep -i -e bcm43xx -e b43 -e ssb -e wl -e ndiswrapper
lshw -C network
cat /etc/modprobe.d/blacklist*|grep -i -e bcm43xx -e b43 -e ssb -e wl -e ndiswrapper
cat /etc/modules|grep -i -e bcm43xx -e b43 -e ssb -e wl -e ndiswrapper
Here is a command to try to see if you can get connected. It is a temporary command that will only last for the current session:
The first command is the module remover. We will take out all the possible modules for your card. The next command will rebuild the module dependencies. The last command will load the ndiswrapper module.
sudo modprobe -r b43 b43legacy ssb bcm43xx wl ndiswrapper
sudo depmod -ae
sudo modprobe ndiswrapper